Fluid-motion apparatus

ABSTRACT

Fluid compressor, pump, or like fluid-motion apparatus having rotor with blades interposed in a housing chamber intermediate the fluid inlet and discharge ports. The blades have relieved areas formed in the lateral edges thereof which interface a wall of the chamber to communicate a high-fluid pressure zone on the one side of said blades with a low-fluid pressure zone at the other side of said blade, thereby to control the fluid boundary layer. Further included is a diffuser with similarly relieved areas in the vanes thereof to communicate the disparate pressure zones to either sides of the vanes.

Unite States Patent Davis Feb. 22, 1972 [54] FLUID-MOTION APPARATUS 211Appl.No.: 863,205

[52] 0.8. CI. AIS/211, 415/D1G. l [51] Int. Cl ..F04d l/00, F04d 17/08[58] FieIdofSearch ..4l5/211,119,18l,182,213, 415/212, DIG. l

[56] References Cited UNITED STATES PATENTS 1,622,930 3/1927 Karman etal ..415/D1G. 1 2,819,838 1/1958 Warner ...415/DIG 1 2,847,941 8/1958Jackson 415/DIG. 1 3,068,799 12/1962 Lock ..415/72 1,924,621 8/1933Mueller 415/212 1,350,927 8/1920 Gomborow... 415/119 2,819,838 1/1958Wamer..... 415/211 2,847,941 8/1958 Jackson ....415/l82 2,967,013 1/1961Dallenbach et a1. ..415/l81 3,433,403 3/1969 Gerlitz ..4l5/ l 82 FOREIGNPATENTS OR APPLICATIONS 152,689 10/1920 Great Britain ..4 1 5/211579,770 8/1946 Great Britain... .....4l5/2ll 583,664 12/1946 GreatBritain... .....4l5/119 636,290 4/ 1950 Great Britain ..4 1 5/21 1Murphy [57] ABSTRACT Fluid compressor, pump, or like fluid-motionapparatus having rotor with blades interposed in a housing chamberintermediate the fluid inlet and discharge ports. The blades haverelieved areas formed in the lateral edges thereof which interface awall of the chamber to communicate a high-fluid pressure zone on the oneside of said blades with a low-fluid pressure zone at the other side ofsaid blade, thereby to control the fluid boundary layer. Furtherincluded is a diffuser with similarly relieved areas in the vanesthereof to communicate the disparate pressure zones to either sides ofthe vanes.

9 Claims, 3 Drawing Figures PAIENTEDFEB 22 I972 Pas 3o 1'- FIG.

HIGH PRESSURE SIDE LOW PRESSURE SIDE INVENTOR RA YMO/VD 6. 0A W3 fizzFLUID-MOTION APPARATUS This invention relates to fluid-motion apparatus,such as compressors, pumps and the like, and in particular to suchapparatus having bladed rotors and vaned diffusers and means forcontrolling the fluid boundary layer of the blades and vanes, andfurther and individually to such rotors and diffusers for use influid-motion apparatus.

Conventional fluid-motion devices comprise a bladed rotor rotatablymounted with a shaft, the blades turning in a casing or housing in agiven walled chamber which chamber communicates a fluid inlet with afluid discharge port.

In addition, where the apparatus employs a diffuser, such a diffusernormally comprises a vaned annular, structure disposed about the rotor,interposed in another chamber interposed between the discharge port andthe rotor.

The operating range of such conventional compressors and pumps islimited because the entering direction of the flow relative to theblades of the rotor, and the vanes of diffuser, changes with flow rate.That is, the flow entering direction, relative to the blades and vanes,is a function derived from the flow rate or velocity and the rotorvelocity. The flow direction is the vectored angle resulting from thesetwo velocities. A change in the relative direction of the flow from thedesigned blade and vane angles, i.e., the optimum blade and vane angles,is accompanied by a loss in fluid pressure due to the thickening orbuildup of the boundary layer upon the highprcssure side of the bladesand vanes, In the case of a compressor, the minimum flow limits occurwhen the boundary layer separates from the blade surface and causesstalling of the blade and vane airfoils, and results in a surgingcompressor output. In the case of pumps, the thickening of the boundarylayer reduces the slope of the pressure flow characteristic.

It is an object of the present invention, therefore, to teach afluid-motion apparatus having means for increasing the operating rangethereof by controlling the boundary layer which builds upon the surfacesof the blades ofa rotor and the vanes of a diffuser comprised thereby.

Another object of this invention is to provide an apparatus of the typenoted having a bladed rotor, and comprising means for communicating ahigh-pressure-fluid side of each rotor blade with the low-pressure-fluidside thereof.

Another object of this invention is to provide an apparatus of the typenoted having a vaned diffuser, andcomprising means for communicating ahigh-pressure-fluid side of each diffuser vane with thelow-pressure-fluid side thereof.

Yet another object of this invention is to teach the provisioning ofindividual rotors and diffusers, for use with fluid compressors, pumps,and like fluid-motion apparatus, which have means for communicatingbetween otherwise distinctly separate high-pressure-fluid andlow-pressure-fluid sides of the blades and vanes, respectively, thereofwhich, in cooperation with walled chambers in which they are disposed,define, therebetween, substantially separate fluid pressure zones withlongitudinally extending fluid passages,

A feature of the present invention comprises the provisioning of therotor blades and the diffuser vanes with relieved areas in lateral edgesthereof which are provisioned for an interface with the sidewalls of afluid-motion apparatus housing.

Further objects and features of this invention will become more apparentby reference to the following description taken in conjunction with theaccompanying figures in which:

FIG. 1 is a partial, longitudinal cross-sectional view in elevation of acompressor, having a diffuser, embodying the teaching ofthe invention;

FIG. 2 is a front elevation view of the diffuser vanes and a portion ofthe rotor blades, the view taken along section 2-2 of FIG. 1; and

FIG. 3 is a fragmentary, perspective view of a rotor blade and thewalled chamber from the inlet end.

As shown in FIGS. 1, 2, and 3 a compressor comprises a housing 12 inwhich a rotor 14 is rotatively mounted. The rotor 14 has a plurality ofblades 16 radially disposed thereon. The blades 16 rotate within anannular, walled chamber 18,

and cooperate with the chamber walls to define, therebetween,substantially separate fluid pressure zones which compriselongitudinally extending fluid passages. The chamber communicates ateither ends thereof with a fluid inlet 20 and a outlet 22. A diffuser 24is disposed within the housing 12 and has a plurality of vanes 26radially disposed about rotor 14.

Blades 16 are formed with a relieved area 28 in the entrance or inletend thereof where the blades interface with the wall 30 of the housing12. The relieved area 28 cooperates with the wall 30 to present a gap 32between the blade and the wall in chamber 18.

The diffuser 24 also has plurality of gaps formed by the vanes thereofby the provisioning of relieved areas 34 to either sides of each vane26, again at the entrance or inlet end thereof. Here too, relieved areas34 cooperate with wall surfaces 30 and 38 to define gaps 40, at theentrance end of a second, annular, walled chamber 2 defined by walls 36and 38.

In the embodiments shown in FIGS. 1, 2, and 3, my invention teaches theuse of plurality of gaps 40 for each diffuser vane 26 and a single gap32 for each of the rotor blades 16. However, this is done only by way ofexample, for it has been shown by experiment that the use of a singlegap for each diffuser vane will function substantially as effectively,in accordance with the teaching of my invention; more, a single gap 40is more easily fabricated.

The purpose of the gaps 32 and 40 is to equalize the pressure differenceacross the blades 16 and vanes 26, which is excessive at large angles ofattack. It also provides circulation of the fluid from the high-pressureside to the low-pressure side of the blades and vanes which, in turn,energizes the fluid boundary layer. The boundary layer would otherwisetend to build up on the high-pressure side of the vanes 26 and blades16.

Laboratory tests of a diffuser with these gaps 40, circulating gaps(so-called to denote the facility with which they circulate thedisparate fluid pressure to either sides thereof), reduced the flow rateat diffuser stall to 55 percent of the stall flow of the standarddiffuser (i.e., a diffuser without circulating gaps). At this lowerflow, the pressure rise was 25 percent higher than in a standarddiffuser.

Through my disclosure, those skilled in this art will find it possibleto practice my invention through other embodiments thereof. Forinstance, rather than providing relieved areas 28 and 34 in the lateraledges of the blades 16 and vanes 26, respectively, the circulating gaps32 and 40 can be otherwise provisioned. For instance, a portion of wall30 can be undercut, to define an annular-relieved surface thereatadjacent the entrance ends of blades 16, and the same can be done withrespect to walls 36 and 38 at the entrance end of the diffuser 24.

Accordingly, while I have described my invention in connection withspecific embodiments thereof it is to be clearly understood that this isdone only by way of example and not as a limitation to the scope of myinvention as set forth in the objects thereof.

Iclaim:

1. A fluid-motion apparatus, such as a fluid compressor, pump, or thelike, comprising:

a housing;

a rotor rotatably mounted in said housing;

means for admitting fluid to said housing;

means for discharging fluid from said housing;

first walled chamber means communicating said admitting and dischargingmeans;

said rotor having a plurality of primary elements carried radiallythereabout, interposed between said admitting and discharging means, forworking engagement thereof with said fluid, said primary elements beingcooperative with one wall of said chamber means to define, therebetween,substantially separate, longitudinally extending fluid passages;

said primary elements each further defining given high-pressure andlow-pressure fluid zones to either sides thereof;

pump, or the like, comprising:

said elements having first outer radial edge surfaces which form aninterface with second surfaces of said one wall of said chamber means;and

at least one of said first and second surfaces has a materialremovedarea, with surfacing which diverges away from said interface, whichdefines a recess which opens on both said high-pressure and low-pressurezones effective for communicating said highand low-pressure fluid zonesto control the fluid boundary layer which forms on said elements; andwherein said recess is formed at only one given location in said onesurface for effecting said communication of said zones intermediate theends of said passages.

2. A fluid-motion apparatus, such as a fluid compressor,

pump, or the like, comprising:

a housing;

a rotor rotatably mounted in said housing;

means for admitting fluid to said housing;

means for discharging fluid from said housing;

first walled chamber means communicating said admitting and dischargingmeans;

said rotor having a plurality of primary elements carried radiallythereabout, interposed between said admitting and discharging means, forworking engagement thereof with said fluid, said primary elements beingcooperative with one wall of said chamber means to define, therebetween,substantially separate, longitudinally extending fluid passages;

said primary elements each further defining given high-pressure andlow-pressure fluid zones to either sides thereof on the rotationthereof;

said elements having first outer radial edge surfaces which form aninterface with second surfaces of said one wall of said chamber means;and

at least one of said first and second surfaces has a recess formedtherein effective for communicating said highand low-pressure fluidzones to control the fluid boundary layer which forms on said elements;and wherein said elements comprise blades,

said blades each having a configuration in general conformity with thatof said first chamber, and

said recess comprises a material-relieved area formed in at least oneradial edge of said blades, said area having surfacing which divergesaway from said one wall of said chamber means and which cooperates withsaid one wall of said chamber means to define a gap therebetween whichopens on both said high-pressure and said lowpressure zones.

3. A fluid-motion apparatus, according to claim 2, wherein:

said blades each have a given length; and

said relieved area extends for a limited distance along said length todefine said gap intermediate the ends of said blade.

4. A fluid-motion apparatus, according to claim 2, wherein:

said relieved area extends into the terminal face of said blade which isdisposed adjacent to said fluid admitting means.

5. A fluid-motion apparatus, such as a fluid compressor,

a housing;

a rotor rotatably mounted in said housing;

means for admitting fluid to said housing;

means for discharging fluid from said housing;

first walled chambermeans communicating said admitting and dischargingmeans; 1

said rotor having a plurality of primary elements carried radiallythereabout, interposed between said admitting and discharging means, forworking engagement thereof with said fluid, said primary elements beingcooperative with walls of said chamber means to define, therebetween,substantially separate, longitudinally extending fluid passages;

said primary elements each further defining given high-pressure andlow-pressure fluid zones to either sides thereof; said elements havingfirst surfaces ad acent to said fluid-admitting means which interfacewith second surface of said first chamber means; and

at least one of said first and second surfaces has a recess formedtherein for communicating said highand lowpressure fluid zones tocontrol the fluid boundary layer which forms on said elements wherein;

said recess is formed at a given location in said one surface foreffecting said communication of said zones intermediate the ends of saidpassages; and further including diffuser means disposed between saidrotor and discharging means, in second walled chamber means formed insaid housing;

said diffuser means comprising a plurality of secondary elementsradially disposed relative to said rotor, for working engagement thereofwith said fluid,

said secondary elements each comprises means defining otherhigh-pressure and low-pressure fluid zones to either sides thereof;

said secondary elements having third surfaces adjacent to saidfluid-admitting means which interface with fourth surfaces of saidsecond chamber means; and

at least one of said third and fourth surfaces comprise other means forcommunicating said other highand low-pressure fluid zones to control thefluid boundary layer which forms on said secondary elements.

6. A fluid-motion apparatus, according to claim 5, wherein:

said secondary elements each have a given length, and

said other means comprise means for effecting said communicating of saidother zones intermediate said length.

7. A fluid-motion apparatus, according to claim 5, wherein:

said secondary elements comprise vanes,

said vanes each having a configuration in general conformity with thatof said second chamber, and

said other means comprises a relieved area formed in at least onelateral edge of said vanes, said vane-edge area cooperating with saidone wall of said second chamber to define a gap therebetween.

8. A fluid-motion apparatus, according to claim 7, wherein:

said vanes each have a given length; and

said vane-edge area extends for a given distance along said length todefine said gap intermediate the ends of said vane.

9. A fluid-motion apparatus, according to claim 7, wherein:

said vane-edge area extends into the terminal face of said vane which isdisposed adjacent to said fluid discharging means.

1. A fluid-motion apparatus, such as a fluid compressor, pump, or thelike, comprising: a housing; a rotor rotatably mounted in said housing;means for admitting fluid to said housing; means for discharging fluidfrom said housing; first walled chamber means communicating saidadmitting and discharging means; said rotor having a plurality ofprimary elements carried radially thereabout, interposed between saidadmitting and discharging means, for working engagement thereof withsaid fluid, said primary elements being cooperative with one wall ofsaid chamber means to define, therebetween, substantially separate,longitudinally extending fluid passages; said primary elements eachfurther defining given high-pressure and low-pressure fluid zones toeither sides thereof; said elements having first outer radial edgesurfaces which form an interface with second surfaces of said one wallof said chamber means; and at least one of said first and secondsurfaces has a materialremoved area, with surfacing which diverges awayfrom said interface, which defines a recess which opens on both saidhigh-pressure and low-pressure zones effective for communicating saidhigh- and low-pressure fluid zones to control the fluid boundary layerwhich forms on said elements; and wherein said recess is formed at onlyone given location in said one surface for effecting said communicationof said zones intermediate the ends of said passages.
 2. A fluid-motionapparatus, such as a fluid compressor, pump, or the like, comprising: ahousing; a rotor rotatably mounted in said housing; means for admittingfluid to said housing; means for discharging fluid from said housing;first walled chamber means communicating said admitting and dischargingmeans; said rotor having a plurality of primary elements carriedradially thereabout, interposed between said admitting and dischargingmeans, for working engagement thereof with said fluid, said primaryelements being cooperative with one wall of said chamber means todefine, therebetween, substantially separate, longitudinally extendingfluid passages; said primary elements each further defining givenhigh-pressure and low-pressure fluid zones to either sides thereof onthe rotation thereof; said elements having first outer radial edgesurfaces which form an interface with second surfaces of said one wallof said chamber means; and at least one of said first and secondsurfaces has a recess formed therein effective for communicating saidhigh- and low-pressure fluid zones to control the fluid boundary layerwhich forms on said elements; and wherein said elements comprise blades,said blades each having a configuration in general conformity with thatof said first chamber, and said recess comprises a material-relievedarea formed in at least one radial edge of said blades, said area havingsurfacing which diverges away from said one wall of said chamber meansand which cooperates with said one wall of said chamber means to definea gap therebetween which opens on both said high-pressure and saidlow-pressure zones.
 3. A fluid-motion apparatus, according to claim 2,wherein: said blades each have a given length; and said relieved areaextends for a limited distance along said length to define said gapintermediate the ends of said blade.
 4. A fluid-motion apparatus,according to claim 2, wherein: said relieved area extends into theterminal face of said blade which is disposed adjacent to said fluidadmitting means.
 5. A fluid-motion apparatus, such as a fluidcompressor, pump, or the like, comprising: a housing; a rotor rotatablymounted in said housing; means for admitting fluid to said housing;means for discharging fluid from said housing; first walled chambermeans communicating said admitting and discharging means; said rotorhaving a plurality of primary elements carried radially thereabout,interposed between said admitting and discharging means, for workingengagement thereof with said fluid, said primary elements beingcooperative with walls of said chamber means to define, therebetween,substantially separate, longitudinally extending fluid passages; saidprimary elements each further defining given high-pressure andlow-pressure fluid zones to either sides thereof; said elements havingfirst surfaces adjacent to said fluid-admitting means which interfacewith second surface of said first chamber means; and at least one ofsaid first and second surfaces has a recess formed therein forcommunicating said high- and low-pressure fluid zones to control thefluid boundary layer which forms on said elements wherein; said recessis formed at a given location in said one surface for effecting saidcommunication of said zones intermediate the ends of said passages; andfurther including diffuser means disposed between said rotor anddischarging means, in second walled chamber means formed in saidhousing; said diffuser means comprising a plurality of secondaryelements radially disposed relative to said rotor, for workingengagement thereof with said fluid, said secondary elements eachcomprises means defining other high-pressure and low-pressure fluidzones to either sides thereof; said secondary elements having thirdsurfaces adjacent to said fluid-admitting means which interface withfourth surfaces of said second chamber means; and at least one of saidthird and fourth surfaces comprise other means for communicating saidother high- and low-pressure fluid zones to control the fluid boundarylayer which forms on said secondary elements.
 6. A fluid-motionapparatus, according to claim 5, wherein: said secondary elements eachhave a given length, and said other means comprise means for effectingsaid communicating of said other zones intermediate said length.
 7. Afluid-motion apparatus, according to claim 5, wherein: said secondaryelements comprise vanes, said vanes each having a configuration ingeneral conformity with that of said second chamber, and said othermeans comprises a relieved area formed in at least one lateral edge ofsaid vanes, said vane-edge area cooperating with said one wall of saidsecond chamber to define a gap therebetween.
 8. A fluid-motionapparatus, according to claim 7, wherein: said vanes each have a givenlength; and said vane-edge area extends for a given distance along saidlength to define said gap intermediate the ends of said vane.
 9. Afluid-motion apparatus, according to claim 7, wherein: said vane-edgearea extends into the terminal face of said vane which is disposedadjacent to said fluid discharging means.